Improvement



MARSHALL GATES, OF GWATONNA, MINNESOTA.

IMPRVEMNT IN HT-AiR FURNACES.

Specification forming part of Letters Patent No. ll, dated March 17,1574; application filed February 9, 1874.

To all whom fit may concern:

Be it known that l, MARsHALL GATES, of Owatonna, in the county of Steeleand in the State of Minnesota, have invented certain new and usef'ulImprovements in Hot-Air Furnaces; andA do hereby declare that thefollowing is a full, clear, and exact description thereof, referencebeing had to the accompanying drawings, making a part of thisspecification, in which- Figure l is a perspective view of my apparatuswith the ca-sing removed, and Fig. 2 is a vertical central section on aline extending from front to rear.

Letters ,of like name and kind refer to like parts in each figure.

The present invention has for its object the construction andarrangement of a hot-air furnace in such a manner that the lcrgest percent. of heat from the products of combustion shall be utilized forwarming the apartments of the house in which the furnace is used; and itconsists in combining with the fire-chamber a supplementary chamber ofcombustion and drums, in and through which are passages for theradiation and circulation of heat and air, and all so arranged that theproducts of combustion shall be compelled to traverse the length of thefurnace at least twice .before it escapes into the chimney; and in soconstructing the furnace that an air chamber or space is provided undernearly the entire lower parts thereof, whereby the heat is radiatedfreely from these parts of the furnace, and, by means of suitablepassages in and from said chamber, caused to circulate and escapereadily into the main hot-air chamber of the furnace.

In the drawing, A designates the tire-chamber. This is usually made ofboiler-iron, and has cast-iron heads, the front one of which is fixed toand upon the outer front wall by suitable flanges, and the rear one isset rmly against the walls of the supplemental combustion-chamber B. Ais the furnace-door, a, the draft-openings; a', the smoke-exit into thesupplemental chamber of combustion B. This chamber is usually inclosedat its sides by brick walls. These are built up from the bot- The rearwall of the furnace and the rear end of the fire-chamber close thisair-chamber at the two ends. Transversely through these walls, andthrough said chamber, are air-pipes B. In the top of said chamber, whichis usually made of sheet-iron, and at the part of the chamber nearly theremotest from the point at which the products of combustion enter it,

is the exit-pipe D. This has an elbow, which connects said chamber withthe drum E at a point about equidistant from its ends. Said drum is anannulus, and the opening E constitutes an opening or aperture for theradiation of heat from the vinner periphery of the annulus, and for thecirculation of air.' On the side of this drum opposite to that in whichthe pipe D enters, and near the ends, are two pipes, c e. These enterthe second drum, E', which is constructed in like manner as the drum E,and connected with the next by a single pipe, c. In the drawing, l haveshown four of these drums thus made and arranged and connected 5 but itis evident that I can use as few or as many of them as I choose, theobject being to make the longest possible passage for the flow of theproducts of combustion, and afford the greatest surface for theradiation of heat. These drums are arranged horizontally, and usuallyfill the distance between the rear and front wall of the furnacecasin g,extending entirely over the supplemental chamber of combustion and thefirechamber, but placed so far above them as to allow a circulation ofair and a free radiation of heat from the outer surface of all theseparts. Ordinarily, I so arrange these drums that the pipe F, issuingfrom the last, comes from a point near the center, like as the pipe Dentered the first drum. This pipe has suitable provision, by elbows orconnections, to lead it through the top G of the furnace. This top Iusually construct of sheet metal, and't it at its edges upon rabbets inthe top of the furnace-walls, so that it is sufficiently below the upperedges of these walls to allow a layer of bricks to be placed upon it.These bricks cover the entire surface, excepting in the places whereapertures or thimbles H are provided for the reception of the pipeswhich convey the hot air to the various apartments to be heated. Thesebricks serve to prevent, in a erture I in the rear Wall.

good measure, the radiation of heat from this top, and to insure, in agreater degree, this non-radiation of heat, I sometimes streW sandfreely over the top of the bricks. I can also use rods or bars,extending them from side to side, as further supports for thissheet-metal top.

For the purpose of cleaning out the furnace or admitting air into theheating-chamber, I have provided a door in one of the walls. There mayalso be another door over the ap- This aperture serves to admit air intothe chamber C beneath the supplemental chamber of combustion, and thespace C beneath the nre-chamber. This latter space is merely acontinuation and contraction of chamber C. The air becomes considerablyheated here, and then escapes into the main heating-chamber throughapertures z', which are placed at convenient points on each side nearthe iioor. By means of these chambers and this circulation of air, I amable to insure a better and more complete radiation of heat from theunder parts of the furnace proper, and to utilize a portion of theheating power which is ordinarily Wasted. K is a clean-out aperture inthe rear of the supplemental chamber of combustion. L is a Waterpan,which is designed to be pushed in or pulled out through a suitableaperture in the Wall of the furnace, and, when thus set in place, restsupon the top of the supplemental chamber of combustion. This Water-panmay have a handle, or be provided With any suitable means for moving itback and forth.

In the drawing, I have made no special provision for dampers, but Idesign to have them placed at such points in the pipes a', D, and F asmay best answer the purposes of checkiu g the dra-ft, according to theparticular needs of the location in which the furnace is placed.

-In some instances the draft may be so great as to render more dampersnecessary than in others. I Wish to put them in or leave them out, asmay be best, according to the condition of the individual use of thefurnace. The device, as thus made and arranged, is chiefly used forburning Wood.

By the peculiar arrangement of the parts of my device, the smoke andescaping products of combustion are caused to malte a lon g and mostcircuitous passage after leaving the fire-chamber before they finally gooff at the outlet-pipe, and, in their course, they pass over so great anextent of radiating-surfaceto Wit, in the first instance, in the chamberB, and then in the drums E E', 85e., with all theirconnecting-pipes--that they give out a very large proportion of theirheat.

The construction of this furnace is such that it can be forced to itsmaximum heating capacity in the shortest time, since the material ofwhich it is chiefly constructed is thin metal, and this high state ofcombustion can be maintained Without the least inconvenience; and, onthe other hand, the furnace can be run or combustion maintained at avery low degree of temperature. Thus, in the extreme cold Weather of ourmore northern states, this device is admirably adapted for use duringthe entire period when a heater is needed. It can be used With theminimum of fuel in the cool days of fall and spring, or With the maximumWhen the rigors of the Winter set in.

Having thus fully set forth the nature and merits of my invention, whatI claim as new 1s- 1. In a hot-air furnace, substantially as described,the fire-chamber A, supplemental combustion-chamber B, air-pipes B', anddrums E E', Svc., the several parts being arranged and combined in themanner and by the means set forth.

2. The combination of air-chambers C and C', having air inlet and exitopenings, as dcscribed, with the fre-chamber A, supplementalcombustion-chamber B, air-pipes B', and drums E E', Ste., in a hot-airfurnace, substantially in the manner and for the purposes set forth.

In testimony that I claim the foregoing I have hereunto set my hand this5th day of February, 1874.

MARSHALL GATES. Vitnesses:

GEORGE W. PAYNE, T. G. PATCH.

